Delayed Onset Muscle Soreness (DOMS)

There are several topics within exercise science that are not well understood and delayed onset muscle soreness or DOMS is one of them.

DOMS is a familiar experience for athletes at every level and can be described as muscles soreness that occurs 24 - 48 hours following intense exercise. The sensation can range from mild discomfort to debilitating pain.

Delayed onset muscle soreness differs from the acute muscle soreness that can be felt during or immediately following a heavy exercise bout. This is usually attributable to an increase in hydrogen ions associated with lactic acid accumulation or edema that build up of fluid in the tissues often referred to by bodybuilders as being pumped-up.

Several theories have been proposed to explain the underlying cause of delayed onset muscle soreness, however none is universally accepted. There are also many anecdotal claims that the effects of DOMS can be reduced with various treatment modalities. Again, no method has any conclusive, empirical support; likewise for the prevention of delayed onset muscle soreness.

Causes of Delayed Onset Muscle Soreness

Although the actual pathophysiology of DOMS is debateable, most researchers agree that it results from strenuous eccentric muscle action (1).

Stone and co-workers (2) found that static and concentric muscle actions caused little or no delayed soreness compared to the extreme soreness felt with eccentric resistance training.

Studies on endurance-based activity have found that the eccentric bias of running downhill on a treadmill results in a significantly higher level of delayed onset muscle soreness compared to running on the flat (3,4). This is a phenomenon many fell runners can testify to!

Lactic Acid
Lactic acid and its accumulation was once thought to be a major cause of DOMS, however this is not the case. Blood lactate returns to resting levels within one hour of exercise even after extremely intense bouts of work (5). The studies on downhill running (3,4) found that although it resulted in greater DOMS compared to level running, it produced significantly less blood lactate accumulation.

Tissue Breakdown
Delayed onset muscle soreness may be the result of muscle tissue breakdown. Muscle biopsies taken from marathon runners after competition or training, have highlighted considerable cell damage in these athletes muscles (7). The sarcolemma (cell membrane) may be ruptured (6) allowing the contents of the cell to seep between other muscle fibers. Damage to the contractile filaments actin and myosin as well as the z disc configuration (responsible for structural support), has also been reported (7).

Inflammatory Response
Heavy exercise of the kind that results in DOMS can often induce an immune system response. White blood cell count has been shown to increase following strenuous activity (8,9). This has led to the hypothesis that DOMS is caused by an inflammatory response in the muscles.

In an attempt to attenuate the effects of delayed onset muscle soreness, researchers have tried administering athletes with anti-inflammatory drugs. However, this approach has been unsuccessful at reducing either the occurrence or severity of soreness. More recently, it has been found that microscopic muscle damage caused by heavy exercise may indeed cause an inflammatory response in the muscles. See Tidall (10) for an in-depth discussion on the inflammatory cell response to acute muscle injury.

It seems likely that acute structural damage to muscle tissues initiates the occurrence of DOMS. This could then set up a chain of events that leads to necrosis (cell death) peaking about 48 hours after exercise. Intracellular contents and the by-products of an immuno-response then accumulate outside the cells stimulating the nerve endings of the muscle (11).

Reducing the Effects of Delayed Onset Muscle Soreness

DOMS results in loss of maximal force and can reduce performance in a 1-repetiton maximum test for example (12). This may be due to three factors:

1) Physical damage to the muscle tissue
2) Failure of the excitation-contraction coupling
3) Loss of contractile protein

DOMS also results in a loss of range of motion and muscle recruitment patterns (18).

No method has been shown to significantly speed the recovery from delayed onset muscle soreness.

Massage has shown varying results that may be attributed to the time of massage application and the type of massage technique used. It can reduce the discomfort associated with DOMS (13,14,15) and perhaps even swelling (13) but does not seem to affect muscle function (13,14,15). Cryotherapy (ice baths or ice packs) (16,17), stretching (18), homeopathy (19), ultrasound (20) and electrical current modalities (21,22) have demonstrated no effect in clinical trials on the alleviation of muscle soreness or other DOMS related effects.

Vitamin C plays a role in repairing connective tissue and anecdotal reports suggest that antioxidant supplementation can attenuate the effects of delayed onset muscle soreness. However, this is not confirmed by clinical trials (23,24, 25). Taking vitamin C in large doses is not recommended and can, in some cases, be harmful.

Finally, a recent study by Miller and co-workers (26) demonstrated the effectiveness of a protease supplement on the prevention and recovery from DOMS...

The experimental group demonstrated significantly superior recovery of contractile function and diminished effects of delayed onset muscle soreness after downhill running when compared with a placebo group.

Although intense exercise, particularly after a prolonged layoff from activity, can cause DOMS, subsequent training sessions are less likely to result in delayed soreness (13).